The Seroconversion Surveillance Project is a collaborative project of the FDA, the National Hemophilia Foundation, and the Centers for Disease Control designed to assess the risk of HIV infection from currently licensed clotting factor concentrates. Data are collected through questionnaires sent to Hemophilia Treatment Center and by telephone interviews with representatives of those centers. Information sought pertains to numbers of patients treated at the Center, testing results on patients, and products used. Any HIV seroconversions are investigated to determine if the infection can be attributed to use of a particular product. If so, the manufacturing processes used in preparation of the product and the current availability of the product are established. Thus far, no seroconversions have been identified in which currently available products are implicated.